Intelligent machines and process for production of monocrystalline products with goniometer continual feedback

ABSTRACT

The present invention consists of an x-ray goniometer which is positioned directly adjacent to processing machines used in the cutting, milling, drilling and shaping of crystal boules and crystal ingots, used in conjunction with an adjustable tilt platform capable of pitch, yaw and roll movement, to allow in-situ measurement and automatic adjustment of crystal orientation with respect to the processing machine. The goniometer may be secured to either the tool itself or a portion of the machine which is adjacent the piece to be worked. Various embodiments include an x-ray goniometer and adjustable tilt platform incorporated into a core drilling machine, wire saw, surface grinder, polishing apparatus, or orientation flat or notch grinder. Incorporating an x-ray goniometer and adjustable tilt platform directly into a crystal processing machine results in a significant decrease in overall processing time and labor, and a significant increase in precision when processing crystal ingots into a final product, such as a notched wafer.

FIELD OF THE INVENTION

The present invention relates to the field of intelligent machines whichare utilized for creating monocrystalline products wherein anorientation device, namely an x-ray goniometer, is mounted directlyadjacent the machining apparatus, which utilizes an adjustable tiltplatform such that immediate crystal orientation feedback and adjustmentoccurs both before and after processing, and at regular intervals duringthe creation of monocrystalline devices such as ingots, wafers andchips, in order to consistently obtain final products within closetolerances while decreasing product processing time and enhancingproduct quality.

BACKGROUND OF THE INVENTION

Processed crystals have increased in demand due to their usefulness as asubstrate in a variety of electronic components such as galliumnitride-compound semiconductors. Such uses, however, require the crystalsubstrate surface to be precisely oriented. In order to achieve aprecise orientation, the crystal substrate must be meticulouslyprocessed. X-ray goniometers have been indispensable in this regard, asinstruments used to determine the correct crystal plane prior toprocessing.

An x-ray goniometer is an apparatus designed to measure the anglebetween crystalline orientation. It comprises an x-ray source, acollimator, a specimen, and an x-ray detector. The collimator confinesthe x-ray source to a narrow beam that is directed toward the specimen.As the x-rays encounter the specimen, some are diffracted toward thedetector. The diffracted x-rays behave according to the Bragg Equation:

nλ=2d(sin θ)

where lambda, λ, is the wavelength in Angstroms of the diffractedx-rays, theta, θ, is one-half of the diffraction angle 2θ, and is theangle between the incident x-rays and the scattering planes. Thedistance between the crystalline lattice planes, d, is measured inAngstroms.

There are many difficulties associated with the manufacture andprocessing of monocrystalline materials for use in electronic devices.For example, the process begins when a crystal boule is placed on aplatform and an x-ray goniometer is used to measure the orientation ofthe crystals. After the crystal orientation has been determined, theboule is marked and adhesive is used to rigidly and removably secure theboule to a machine fixture, in order to maintain proper orientation ofthe boule with respect to the drilling machine. The machine fixturecommonly consists of an aluminum or graphite board. After the boule isfixed to the machine fixture and loaded into the core drilling machine,the crystal orientation is again measured to ensure that the boule hasnot shifted its position during the curing process for the adhesive. Ifthe boule does not remain oriented correctly, as is often the case, itmust be forcibly removed from the substrate and the process is repeated,wasting precious time and resources. This process continues until theboule is aligned and fixed properly to the substrate. Often this cantake 7 to 10 repetitions or more until the boule is positionedcorrectly.

Once positioned correctly, the boule is then transferred to a coredrilling machine, which produces cylindrically shaped ingots. The finalorientation for the ingot must be accurate, within a tolerance of ±2arc-minutes, or 1/30 of a degree. To correct for variability of crystalorientation, conventional processing will commonly produce an ingot thatis substantially larger than needed. The ingots will again be measuredwith an x-ray goniometer and their surfaces will be ground further toproduce an ingot with the required orientation. This often requiresnumerous measurement-grinding iterations.

What is lacking in the prior art is a system and machine assembly whichdoes not make use of this repetitive and iterative process of drilling,grinding, or other crystal machining and still maintains proper crystalorientation throughout processing. This is accomplished by integratingthe functions of crystal structure determination and automatic alignmentof the crystal into the processing machine. A number of patents anddisclosures relate or refer to this area and crystal processing.

The McCarty Patent, U.S. Pat. No. 2,425,750, discloses a device foraligning a crystal using light, wherein a cutting tool can replace thealigning tool after the crystal is measured. This reference does notdisclose a tool using x-rays, or a tool that has both the cutting tooland the measuring tool integral to the assembly.

The Coleman Patent, U.S. Pat. No. 2,556,167, discloses a crystalanalysis apparatus that has an improved jig for holding crystals whiledetermining their orientation and facilitates easy transfer to a cuttingsurface. It does not disclose a device where an x-ray goniometer andcutting tool are combined into one tool.

The Kumada Patent, U.S. Pat. No. 3,838,678, discloses an apparatus wherea crystal is measured with x-ray radiation and then moved onto aseparate area with a cutting device at a predetermined angle. Thisreference does not disclose an apparatus having an x-ray goniometerwhich is able to measure a crystal without having to subsequently movethe crystal to process it.

The Frederick Patent, U.S. Pat. No. 4,002,410, discloses a small deviceto removably secure a crystal in order to determine the orientation forsawing by transmitting a series of light beams and interpreting thepattern. It does not disclose a device that has an integratedmeasurement and sawing tool, nor does the disclosed device utilizex-rays to determine crystal orientation.

The Causey Patent, U.S. Pat. No. 4,331,452, discloses a crystal shapingapparatus having means for x-ray determination of crystal orientationand an apparatus to grind an orientation flat upon the wafer, therebycreating a crystal blank. This reference does not disclose a device witha built in x-ray crystal detection device for cutting or grinding acrystal.

The Brinkgreve Patent, U.S. Pat. No. 4,637,041, discloses an x-rayanalysis apparatus with a rotatable arm for which the mutualdisplacement and orientation of components is executed in such a mannerthat it permits reproducible adjustment of the components with respectto one another. It does not disclose an x-ray analysis tool withintegrated crystal processing tools.

The Rinik Patent, U.S. Pat No. 4,649,556, discloses a method andapparatus for “on-line” nondestructive measurement of grain size ofvarious materials using a monochromatic beam of x-rays to allow actionssuch as corrective actions to quickly occur, and measure movingmaterials. It does not disclose a goniometric method of determiningcrystallographic orientation, or a crystal processing apparatus.

The Howe Patent, U.S. Pat. No. 4,788,702, discloses a method fordetermining the orientation of a single crystal which utilizes a crystalon a turntable and a stationary position-sensitive detector which isable to complete this process in a completely automated manner. Thisreference does not disclose a measuring device that is integrated into aprocessing device.

The Vanderwater Patent, U.S. Pat. No. 4,884,887, discloses a method ofdetermining crystal orientation which uses the processing machine as areference frame to simplify the process, and further uses a U-shapedmember, which when held at a particular distance, causes the body of thecrystal to come into contact with both ends of the member. It does notdisclose a method which incorporates both crystal orientationdetermination and crystal processing in one apparatus.

The Ibe et al. Patent, U.S. Pat. No. 5,187,729, discloses a method andapparatus for determining the orientation flat of a crystal by rotatingthe ingot about a single axis only, using x-ray diffraction to determinethe orientation, and then grinding the orientation flat. It does notdisclose a method whereby x-ray analysis is integrated into subsequentpolishing or cutting steps; nor does it disclose a method for crystalprocessing of boules or wafers.

The Hirano Patent, U.S. Pat. No. 5,405,285, discloses a machine errorcorrection apparatus in which machine errors are measured and thentransmitted into the memory of a grinding device, which uses thatinformation to correct the errors while grinding. This invention doesnot disclose a grinding device combined with an orientation measurementdevice.

The Hirano Patent, U.S. Pat. No. 5,484,326, discloses a method forprocessing a crystal whereby a crystal is ground down, measured withx-rays to determine its orientation, and then subsequently ground withan orientation flat. This reference does not disclose a method where acrystal cutting or polishing process includes an integrated x-rayanalysis apparatus.

The Miller Patent, U.S. Pat. No. 5,529,051, discloses a method ofpreparing wafers where silicon wafers are sawn from ingots on the (100)reference plane, using the reference planes to determine ingotorientation, as opposed to x-ray analysis. This reference does notdisclose a method of producing crystal wafers using x-ray analysis inconjunction with a method of processing ingots.

The Grueninger Patent, U.S. Pat. No. 5,640,437, discloses a goniometerwith a radiation detector, a Bragg Detector, and a fluorescent detectorcombined into one device. This device does not include any additionalfunctions for cutting or otherwise processing boules, ingots, or wafers.

The Hauser Patent, U.S. Pat. No. 5,720,271, discloses a process andapparatus for orienting a crystal to a particular cutting plane byorienting it on cylinders and positioning it over a plate and thencutting it in accordance with that orientation. This device does notdisclose an x-ray analysis tool with integrated crystal processingtools.

The Shahid Patent, U.S. Pat. No. 5,768,335, discloses an apparatus andmethod for measuring the degree of misorientation of the polishedsurface of a single wafer by utilizing both an optical beam and an x-raybeam to ascertain the difference between the reflected and diffractedbeams with a measuring device containing a detector aligned along atrack. This apparatus and method does not disclose any processing stepssuch as cutting or grinding being carried out by the same device thatmeasures a crystal.

The Hauser Patent, U.S. Pat. No. 5,839,424 discloses, the use of aprocess and device for positioning several single crystals on a supportfor simultaneous cutting utilizing a machine having a rotatable frame, agripping device carrying single crystals, a rotatable gripping supportand a cutting tool. However, this disclosure does not mention or teachthe use of an x-ray goniometer in conjunction with the crystalpositioning and cutting device. The positioning device in the inventionis outside the cutting machine.

The Katamachi et al. Patent, U.S. Pat. No. 5,893,308, discloses the useof a bonding jig which is used to bond a crystal ingot thereto prior tocutting the piece. The horizontal and vertical surfaces of the workpiece bonding block may be aligned parallel to each other. The block isthen fed through a wire saw. The bonding jig may be tilted to adjust thework piece so that the central axis is inclined against the cuttingplane at a predetermined angle on the basis of shift value data of thecrystal orientation. This disclosure does not teach orientationmeasurement and determination within a crystal processing machine.

The Nagatsuka et al. Patent, U.S. Pat. No. 5,904,136, discloses the useof a method and apparatus for cutting crystals which comprises aworkpiece which is attached to a workpiece feed table which is fedthrough a wire saw, wherein the tilt angle of the workpiece has beenadjusted based upon the predetermined crystal orientation outside thewire saw area. The wire saw utilizes a plurality of grooved rollers toform a wire row. The workpiece is attached to a feed table which mayreciprocate with respect to the wire row. In this disclosure, however,the crystal orientation has been determined outside the crystalmachining area.

The Muramatsu Patent, U.S. Pat. No. 5,927,263, discloses the use of amethod for manufacturing circular wafers wherein a specified crystalorientation is detected and the crystal is then mounted upon a supporttable in accordance with the detected crystal orientation. Subsequently,a recognition mark is made upon the top face of the crystal inaccordance with a position of the support. Finally, the support is cutand the workpiece removed. In this disclosure, however, the crystalorientation has been determined outside of the crystal processing area.

The Banzawa Patent, U.S. Pat. No. 6,024,814, discloses a method where aningot is analyzed with a goniometer, and then removably secured to anintermediate base according to the results of that analysis, therebyproperly aligning it with a saw. This patent does not disclose anapparatus or method for measuring an ingot and subsequently processingit without moving the sample in iterative intervening steps.

The Banzawa Patent, U.S. Pat. No. 6,056,031, discloses a method where aningot is measured with an x-ray goniometer, and then transferred to anintermediate surface in a matter which preserves the information aboutthe orientation of the crystal for later processing. It does notdisclose a method of measuring and processing an ingot without anintermediate transfer from one supporting plate to another.

The Katamachi Patent, U.S. Pat. No. 6,145,422, discloses a work piece ona block which is then processed by a wire saw, and it further disclosesprior art where gonio angle measuring meters are mounted on therespective wire saws. This reference does not disclose an x-raygoniometer used with grinding or other processing steps. Nor does thisreference provide for continuous feedback of gonio angles.

The Olkrug Patent, U.S. Pat. No. 6,159,284, discloses a process anddevice for producing a semiconductor wafer by rotating a cylindricalcrystal ingot along two planes of rotation, then the single crystal issecured by pads on either end of the crystal and ground to a uniformdiameter. This reference does not disclose the use of an x-raygoniometer directly in association with a grinding machine.

The Banzawa Patent, U.S. Pat. No. 6,182,729, discloses the use of anapparatus for manufacturing a plurality of wafers by slicing acylindrical ingot with a wire saw. The device consists of a measuringdevice for measuring crystal orientation of the ingot, and an adheringdevice to removably secure the ingot to an intermediate plate and asupport place. This invention does not disclose the use of anorientation measuring device integrated with a crystal processingmachine.

The Blank et al. Patent, U.S. Pat. No. 6,888,920, discloses the use of alow cost high precision goniometric device for use in x-raydiffractography or optical systems which comprises a spherical sectorsupported on at least one bearing, a top surface for mounting an objectthereto, a center of rotation within an object, a rod or other memberdisposed below the spherical bearing surface, motors or actuators toanimate the device and a linkage between the rod and the motors. Thisparticular disclosure does not mention or teach any method suitable fordetermining crystal orientation during cutting, grinding or polishingprocesses.

The Beanland et al. Patent, U.S. Pat. No. 6,977,986, discloses the useof a lithographic tool for printing a pattern from a mask onto a wafertogether with an x-ray diffraction tool for determining crystalorientation. Because the apparatus does not utilize any flats on thewafer for angular alignment purposes, it achieves a higher degree ofaccuracy when aligning crystal planes. Again, this particular disclosuredoes not teach the use of an x-ray crystal alignment device which isintegral to the machine performing cutting, polishing or grindingoperations upon a crystal substance.

The Beanland Patent, U.S. Pat. No. 7,072,441, discloses the use of amethod of alignment for aligning crystalline substances to formlithographic features thereupon including the steps of measuring theorientation of a flat; measuring a crystallographic plane orientation ofthe substrate, determining an error angle; registering the flat via alithographic tool, rotating the crystalline substance by the error angleand marking one or more features on the substance using the lithographictool, thereby angularly aligning the feature layers to the planeorientation. However, this disclosure does not mention or teach anymeans for using an x-ray crystal alignment device which is integral tothe machine performing a cutting, polishing or grinding operationthereupon.

The Hammer et al. Patent, U.S. Pat. No. 7,137,865, discloses the use ofa method for the division of single crystals where a crystal that is tobe cut into at least two parts and a cutting tool are moved relative toone another wherein the crystal will lie in the cutting plane which ischaracterized by an angle

between the crystal's direction and the direction of advancement that ischosen to minimize cutting tool forces on the crystal to be cut.However, this disclosure does not teach the determination of crystalorientation in the machine utilized for processing the crystal, butrather the crystal is mounted and its orientation is determined prior tothe processing step.

The Kikuchi et al. Patent, U.S. Pat. No. 7,158,609, discloses the use ofan x-ray crystal orientation measuring apparatus for mounting thecrystal upon a stage or platform for later processing. Again, theprocessing machine for the crystal does not have an orientation devicewhich is integral to the machine.

Finally, the Bradazcek et al. Patent, U.S. Pat. No. 7,285,168, disclosesthe use of a method and apparatus for the determination of crystalorientation of very hard materials such as sapphire or silicon carbide.A crystal specimen is placed upon a revolving table for determining thecrystal lattice orientation by rotating the table through at least onecomplete revolution. Subsequently a second crystal (or more) may bestacked atop the prior crystal so that multiple crystal items may befurther processed at the same time. However, this particular disclosuredoes not teach any means for incorporating a crystal orientating devicewithin a cutting, polishing or grinding machine.

However, nowhere in the prior art is there seen a system or assemblywherein an x-ray goniometer has been effectively incorporated into amachine which is utilized for the processing of crystalline substancesin order to assure high precision alignment of the interior crystallineorientation during processing. Further, nowhere in the prior art isshown an intelligent machine which continually processes informationreceived from an x-ray goniometer, and adjusts the crystalline substanceaccordingly for the purpose of ensuring proper crystal alignment duringthe entire process of machining a crystalline substance.

SUMMARY OF THE INVENTION

To combat the labor and time intensive inefficiencies and increase thelevel of precision inherent in the current state of the art, the presentinvention comprises a machine assembly that is capable of combining thesteps of measuring the orientation of the crystal lattice planes,maintaining the proper orientation of these planes with respect tomachining tools, and performing the milling/drilling/shaping procedures.It is believed that this concept will lend itself to creating aversatile platform technology which can then be applied to multipleapplications.

The disclosed invention consists of a combination machine assemblyincorporating an x-ray goniometer into various machines used in theprocessing of crystal boules and crystal ingots that also utilizes anadjustable tilt platform so that the orientation of the crystal can bemeasured and adjusted in situ, as well as the process for utilizing sucha device. Various embodiments include the incorporation of an x-raygoniometer and adjustable tilt platform incorporated into a drillingmachine used for the purpose of drilling cylindrical cores from theboule of a crystal material, an x-ray goniometer and adjustable tiltplatform incorporated into a wire saw for the purpose of slicing crystalcores into wafers, an x-ray goniometer and adjustable tilt platformincorporated into the surface grinding application for all crystalforms, including cylindrical cores and wafers, and an x-ray goniometerand adjustable tilt platform incorporated into the process for grindingorientation flats and notches into a crystalline cylindrical core.Incorporating the x-ray goniometer into the processing machines,together with the use of adjustable tilt platforms, reduces the errorthat is introduced when ingots are transferred from one machine thatmeasures the crystal orientation to another machine that processes theingots and reduces errors introduced during the actual processing of thecrystal. Crystal orientation can be repeatedly read and with continuousfeedback, automatically adjusted if necessary to ensure the finalproduct is within the desired tolerance level.

This is accomplished by integrating the goniometer in such a way that itcan withstand the industrial conditions of the milling and drillingprocesses while being positioned so as to measure the crystal planeswithout obstructing the path of the diamond drill bit or other millingor drilling means. It is anticipated that the goniometer will bepositioned such that x-rays will illuminate exactly the targeted pointof the crystal to be operated upon during the various processingoperations such as drilling, surface grinding, flat grinding, wire sawslicing, and the like.

The addition of an adjustable tilt platform, servomotors and feedbackcomputer processing means that this apparatus yields a fully automatedsystem for measuring and processing crystal materials along specifiedcrystal planes. The crystal material is loaded and its initial positionis recorded. Servomotors rotate the crystal boule a discrete amountalong both the x and y axes while the x-ray goniometer produces anoutput signal of the intensity of diffracted x-rays corresponding toeach discrete rotation. The tilt platform capable of pitch, yaw and rollmovement ensures accuracy during the entire machining and x-raydetermination process. The sample data must consist of an x-raydiffraction intensity reading, rotational coordinate along the positiveor negative x-axis, and rotational coordinate along the positive ornegative y-axis. For a specific lattice plane, the sample data iscompared to the known Bragg angle and diffracted beam intensity. As therotation continues, a two-dimensional map of the crystal latticeorientation is obtained. Using this information, the proper orientationplane is identified and the crystal is automatically adjusted using theadjustable tilt platform and servomotors to properly orient the materialwith respect to the machining device. Incorporating servomotors thatmaneuver the crystal material as it is being processed saves a greatamount of time and resources in analyzing and measuring interiorcrystalline orientation during the processing of a crystallinesubstance.

Once a position of proper crystal alignment has been determined by theinventive process, the tilt platform may be locked into position for thesubsequent processing step.

EXAMPLE 1 Core Drilling Application

During typical production of a sapphire crystal wafer, the outerdiameter of the core must be precision ground in relation to theinterior crystal orientation. The required final orientation for ingotsis currently desired to be within a tolerance of ±2 arc minutes.However, with the current capability of core drills, the best toleranceattainable is only ±30 arc minutes. In the past, after drilling, shimswere used in both axial directions during the surface grinding processto obtain the orientation within tolerance after numerous iterations.The cores were drilled with a larger than necessary outer diameter toprovide sufficient outer material for iterative corrections, therebywasting material and final product.

By incorporating an x-ray goniometer into a drilling machine, thegoniometer may be positioned such that x-rays will illuminate the exactcenter point of the core to be drilled. A crystal boule is placed upon atilt platform module, which is then positioned inside the drillingmachine. Orientation of the spot marked for drilling is checked with thegoniometer. Boule orientation can be automatically adjusted using thetilt platform. After the correct orientation has been verified, the tiltplatform is locked into place, the goniometer is moved out of the way,and the core drill bit is positioned in its place. The crystal has beenpositioned exactly with respect to the axis of the drill bit. Crystalorientation can be rechecked and automatically readjusted after apredetermined number of cycles of the machine, in order to ensure thatthe proper orientation is maintained. For the core drilling application,orientation is rechecked and aligned for every predetermined length ofinfeed (for example, for every 1 inch of drilling).

EXAMPLE 2 Wire Saw Application

During typical production of thin annular wafers from a cylindricalingot core, wafers are often sliced into thicknesses ranging from 300 to1300 microns (0.3 to 1.3 millimeters). It is desired that the wafersurface normal be within the required orientation of ±2 arc minutes. Thepresent preparation process involves using adhesive to removably securea crystalline core to a beam and removably secure the beam to a base.The proper positioning of the crystalline core is of utmost importancein that it determines the final orientation of the wafer product.Correct orientation of the final product is only achieved by referencingthe faces of the core with respect to the base of the wire sawapparatus. Instances in which the wafer product is required to have arelatively higher tilt angle are often associated with a higher failurerate.

With the present invention, an x-ray goniometer is incorporated into thewire saw apparatus. The goniometer is positioned such that it is capableof reading the crystal orientation of the core to be sliced after it ispositioned upon the wire saw base. Appropriate adjustments can then beaccomplished automatically through computer feedback processing ormanually by tilting the wire saw base platform. After the core has beenpositioned correctly, is it then locked and the sawing process is theninitiated. Crystal orientation can be rechecked and automaticallyreadjusted at regular intervals, in order to ensure that the properorientation is maintained. For the wire saw application, orientation isrechecked and aligned every predetermined length of infeed (for example,after grinding 100 microns).

EXAMPLE 3 Surface Grinding Machine

During typical production of a crystalline wafer, a cylindrical core ofa crystalline substance must have its end flat surfaces ground in orderto correct the orientation of the crystal, and often numerous timeconsuming iterations are required. In the past much of this processconsisted of a time consuming trial and error procedure.

With the present invention, the entire process may be shortened into onesimple step by incorporating an x-ray goniometer into the surfacegrinding apparatus such that the orientation readings of the interiorcrystalline configuration may be read upon the same face upon which thecore will be ground. The core is automatically adjusted by utilizing acomputer controlled tilt platform to which it is removably secured,after the desired target values of crystalline orientation have beendetermined. Then the base is locked into position and the core is groundin order to achieve the predetermined values in one simple step. Crystalorientation can be rechecked and automatically readjusted after apredetermined number of cycles of the machine, in order to ensure thatthe proper orientation is maintained. For the surface grindingapplication, orientation is rechecked and aligned every predeterminedlength of infeed (for example, after grinding 100 microns).

EXAMPLE 4 Orientation Flat and Notch Grinding Application

During typical production of crystalline cores often the cores aremachined with a notch, groove or flat along a portion of its outerannular portion so that the subsequent users of the product may easilydetermine the interior crystalline configuration of any plane withrespect to where it must be placed for further processing. Often after acrystalline core has been produced it is utilized in subsequentprocesses for slicing, lapping, edge-grinding, polishing and later,imprinting of micro-circuitry or other wafer processes which are highlydependent upon the exact positioning of the wafer surfaces with respectto their interior crystal orientation. If the alignment is not preciseor high tolerances have not been achieved during the manufacture of thecore, the product produced by the subsequent processor will performinadequately, or not at all. Accordingly, the production of a highlyaccurate orientation notch, flat or groove along the edge of the annularcore is essential to producing a high quality end product withinappropriate tolerances for subsequent production procedures.

Typically orientation flat or notch for a C-axis drilled core isparallel to the A-plane. It is crucial to obtain the flat, notch, orgroove with consistent orientation reading throughout its length,together with maintaining a specified flat length.

In accordance with the present invention, an x-ray goniometer isincorporated into an orientation notch, groove, or flat grindingapparatus. With this incorporation, the x-ray goniometer is able todirect the positioning of the core such that consistent readings areobtained along the length of the core, and any corrections may be easilyobtained by manually twisting or moving the core into the properposition or through computer controlled adjustments of a tilt platform.After the required position has been achieved, the core is thenremovably secured to an adjustable tilt platform and flat grinding isthen initiated in order to obtain the correct and consistent orientationreadings along the length of the core. Crystal orientation can berechecked and automatically readjusted after a predetermined number ofcycles of the machine, in order to ensure that the proper orientation ismaintained throughout the entire grinding process. For the coreorientation flat application, the orientation is rechecked and alignedevery predetermined length of infeed (for example, after grinding 50microns).

A similar approach can be followed to grind the orientation flat ornotch on individual wafers.

OBJECTS OF THE INVENTION

Thus, it is one primary object of the present invention to provide animproved system tilt platform for the processing of crystal boules,ingots and the like, whereby processing and machining time isdrastically reduced while at the same time the integrity of theresulting product is significantly enhanced.

It is yet another primary object of the invention to provide a systemplatform for the machining of crystalline products utilizing goniometersand adjustable tilt platforms together with machining tools, which allowcrystal orientation to be determined precisely and adjusted in-situ,thus providing proper orientation without timely and imprecise crystalpositioning iterations between machining steps.

It is yet another primary object of the present invention to provide asystem platform for the machining of crystalline products, wherein saidsystem platform incorporates a goniometer, an adjustable tilt platform,and servomotors communicating with both the goniometer and tiltplatform, such that crystal orientation information may be preciselydetermined in real time during processing, and adjustments to thepositioning of the tilt platform may occur as rapidly as possible,thereby permitting efficient and precise machining of a crystallinematerial.

It is yet another primary object of the present invention to provide atool for the slicing of crystal wafers, wherein said tool comprises awire saw where a goniometer has been provided directly adjacent the wiresaw so that the orientation of the crystal is determined as the crystalis being sliced by the wire saw, and the crystal to be processed ispositioned on an adjustable tilt platform base, thereby allowing crystalrepositioning as the saw may be deforming or biasing the crystalalignment.

It is yet another primary object of the present invention to provide atool for drilling cores of crystal wafers, wherein said tool comprises acore drilling apparatus where a goniometer has been provided adjacent tothe drill so that the orientation of the crystal ingot or boule isdetermined precisely as the crystal is being drilled by the tool, andthe crystal to be processed is positioned on an adjustable tilt platformbase, thereby allowing crystal repositioning as the core drill may bedeforming or biasing the crystal alignment during the machining process.

It is yet a further primary object of the present invention to provide atool for the surface grinding of crystalline products, wherein said toolcomprises a grinder where a goniometer has been provided adjacent to thegrinder so that the orientation of the crystal is determined preciselyas the crystal is being ground into the proper formation by tool, andthe crystal to be processed is positioned on an adjustable tilt platformbase, thereby allowing crystal repositioning as the grinder may bedeforming or biasing the crystal alignment during the machining process.

It is yet a further primary object of the present invention to provide atool for the grinding orientation flats or notches in crystallineproducts, wherein said tool comprises a grinder where a goniometer hasbeen provided adjacent to the grinder so that the orientation of thecrystal is determined precisely as the orientation flat or notch isbeing ground into the crystal by the tool, and the crystal to beprocessed is positioned on an adjustable tilt platform base, therebyallowing crystal repositioning as the grinder may be deforming orbiasing the crystal alignment during the machining process These andother objects and advantages of the present invention can be readilyderived from the following detailed description of the drawings taken inconjunction with the accompanying drawings present herein and should beconsidered as within the overall scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a crystalline core or ingot producthaving an orientation flat.

FIG. 1B is a perspective view of a crystalline core or ingot producthaving an orientation groove/notch.

FIG. 2A is a top perspective elevation of a cylindrical crystallinewafer having an orientation flat.

FIG. 2B is a top perspective elevation of a cylindrical crystallinewafer which has been provided with an orientation groove/notch.

FIG. 3 is a front and left perspective view of a crystal boule mountedwithin a machine fixture with drilling layout (Prior art).

FIG. 4A is a front perspective view of a crystal boule mounted within acore drilling machine utilizing the present invention showing the bouleas it has been cored.

FIG. 4B is a front plan elevation of a display unit containing acomputerized data processing unit for displaying the data relating tothe angle of interior crystal orientation for a particular crystallineitem.

FIG. 4C is a front and top perspective view of a container housing aplurality of crystalline cores having different orientation endsurfaces.

FIG. 5A is a front perspective view of a crystal ingot utilizing thepresent invention mounted onto an adjustable tilt platform andpositioned within a surface grinder.

FIG. 5B is a front perspective view of an individual crystal ingot aftersurface grinding has been performed.

FIG. 6 is a front perspective view of a crystal ingot utilizing thepresent invention mounted onto an adjustable tilt platform andpositioned within an orientation flat/notch grinding machine.

FIG. 7 shows a top isometric view of a wire saw utilizing the presentinvention for proper positioning of the crystalline cores to be slicedinto annular wafers.

FIG. 8 shows a front top perspective view of a housing for annularwafers and a plurality of wafers being retained therein.

DETAILED DESCRIPTION OF THE DRAWINGS

Shown in FIG. 1A is a crystalline core or ingot product 102 having ahighly accurately positioned orientation flat 104 located along itsouter diameter utilizing the present inventive process. Flat 104 hasbeen provided to indicate the correct interior crystal alignment andconfiguration such that ingot product 102 may be accurately positionedinto tools and jigs during subsequent operations. These annular coresare well known and utilized in the prior art. Standards for the size andtype of flats have been established by numerous manufacturers desiringuniformity in use and production and such standards may be found atwww.semi.org on the internet.

Similarly, FIG. 1B shows a crystalline core or ingot product 103 whichhas been provided with a highly accurately positioned orientationgroove/notch 105 located along its outer marginal portion utilizing thepresent inventive process. The groove/notch 105 has been machined forthe purpose of indicating the correct interior crystal alignment andconfiguration for later processing and/or operations. This type ofinterior crystal orientation indication is well known and utilized inthe prior art. Standards for the size and type of grooves have beenestablished by numerous manufacturers desiring uniformity in use andproduction and such standards may be found at www.semi.org on theinternet.

Shown in FIG. 2A is a crystalline wafer product 250 having a highlyaccurately positioned orientation flat 224 located along its outerdiameter utilizing the present inventive process. Flat 224 has beenprovided to indicate the correct interior crystal alignment andconfiguration such that wafer product 102 may be accurately positionedinto tools and jigs during subsequent operations. These annular wafersare well known and utilized in the prior art. Standards for the size andtype of flats have been established by numerous manufacturers desiringuniformity in use and production and such standards may be found atwww.semi.org on the Internet.

Similarly, FIG. 2B shows a crystalline wafer product 250 which has beenprovided with a highly accurately positioned orientation groove/notch225 located along its outer marginal portion utilizing the presentinventive process. The groove/notch 225 has been machined for thepurpose of indicating the correct interior crystal alignment andconfiguration for later processing and/or operations. This type ofinterior crystal orientation indication is well known and utilized inthe prior art. Standards for the size and type of grooves have beenestablished by numerous manufacturers desiring uniformity in use andproduction and such standards may be found at www.semi.org on theInternet.

FIG. 3 depicts the prior art. Here crystal boule 316 is shown beingremovably secured to an x-ray crystal alignment apparatus 300. Thisapparatus consists of mounting platform 322, x-ray emitter 314, x-raycollector 312, rotating mounting plates 310, mounting clamp 318, andfixture clamp pivot 320. Crystal boule 316 is placed on a mountingplatform 322 and secured using the mounting clamp 318. Using therotating mounting plates 310 and the fixture clamp pivot points 320 thecrystal boule 316 is adjusted along the radial direction 330 allowingpitch, roll and yaw. The x-ray emitter 314 and x-ray collector 312 areused to find the correct crystalline orientation of the crystal boule tobe drilled. The crystal boule is manually adjusted for pitch and yaw tofind the desired plane. Once the plane is identified a fine groundaluminum plate 317 is placed below the crystal boule 316 and adhesive313 is used to hold the crystal boule to this plate. The adhesive usedmay be any readily available adhesive in the market. Once the adhesivedries, the crystal boule 316 with the fine ground aluminum plate 317 ismoved to a milling or drilling machine for core drilling operation.

FIG. 4A shows a perspective view of a core drilling apparatus 400 withan x-ray emitter 414 and an x-ray collector 412 positioned above acrystal boule 416 which allows the machine operator to easily andfrequently check the positioning of crystal boule 416 at regularintervals during the core drilling process using the computer dataprocessing unit (FIG. 4B). The output data from the collected x-rays issent to the computer data processing unit 419 and the angle of thecrystalline orientation of the boule is displayed on the LCD display423. The crystal boule 416 is easily repositioned using aservomotor-controlled tilt platform 418. Any instances where the crystalboule 416 has moved from its proper alignment may be quickly andefficiently corrected without removing crystal boule 416 from the coredrilling apparatus 400. Crystal boule 416 is removably secured in placeatop mounting platform 422 using adhesive 413.

Mounting platform 422 is itself affixed to adjustable tilt platform 418,which allows crystal boule 416 to engage in yaw, pitch and rollrotations about z-axis 432, as well as tilt platform translatable y-axis436 and tilt platform translatable x-axis 434 of adjustable tiltplatform 418. Mounting platform 422 commonly comprises an aluminum orgraphite board and the like, which is removably secured to adjustabletilt platform 418 which in turn is removably secured to channeled table420 by means of bolted clamps 438. The adjustable tilt platform 418 isrotatable in roll direction 435 and pitch direction 437. Coring drillbit 430 is preferably edged with diamond powder and moves verticallyalong z-axis 432. For each crystalline core/ingot 450 that is desired(shown in FIG. 4C), the user must adjust the location of crystal boule416 using x-axis turn crank 428 and y-axis turn crank 415 to movecrystal boule's 416 position along the x-axis and y-axis, respectively,until the x-rays emitted by x-ray emitter 414 are aligned with coredrill marking 424 as determined by the display unit. The x-ray emitter414 emits x-rays toward crystal boule 416, which are diffractedaccording to Bragg's Law. Diffracted x-rays are measured using x-raycollector 412 as crystal boule 416 is rotated about rotatable x-axis 434and rotatable y-axis 436 and the Bragg angle is determined by thecomputer data processing unit 419 and displayed on the LCD display 423.After the Bragg angle has been determined, crystal boule 416 is lockedinto place and the x-ray emitter 414 and x-ray collector 412 may beplaced out of the range of slurry or other fouling debris, oralternatively, they may be shielded. Coring drill bit 430 is thenlowered toward crystal boule 416 upon core drill marking 424 andcrystalline core ingot 450 is formed, as shown in FIG. 4C.

This process for obtaining each cylindrical core ingot may be repeatedmultiple times. The checking of the position of the crystal boule 416 inrelation to the core drill bit 430 is anticipated to proceed atregularly timed intervals during the core drilling process. Thus, theadjustable tilt platform 418 and channeled table 420 allows the coringdrill bit 430 to drill multiple crystalline cores 450, as shown in FIG.4C from crystal boule 416 at a plurality of desired angles whileensuring that each core ingot is oriented properly at all times.

FIG. 4C shows a plurality of crystalline ingots 450 that are ready forfurther processing using wire saw assembly 700 shown in FIG. 7. Each ofthese crystalline ingots 450 may have end surfaces with angles that varyaccording to the customer's specifications.

FIG. 5A shows an ingot surface grinding apparatus 500 wherein x-rayemitter 514 and x-ray collector 512 have been mounted to the interior ofthe machine housing for surface grinding apparatus 500 wherein acrystalline ingot 550 may be continuously checked for proper alignmentof its interior crystalline structure. An adjustable tilt platform 518has been provided which allows the crystalline ingot 550 that is securedto the mounting platform 526 to be positioned freely and rotatably aboutz-axis 532, rotatable x-axis 534 and rotatable y-axis 536 as it is beingmachined. Turn crank wheels 528 and 515 are provided which allow theoperator to manually align adjustable tilt platform 518 with respect tosurface grinding apparatus 500 prior to orientation of the crystal withx-ray emitter 514 and x-ray collector 512. Adjustable tilt platform 518is secured to a plurality of table channels 520 via bolted clamps 522.Table assembly 540 reciprocates along the table x-axis 542 and thediamond grinding wheel or similar abrasive wheel 530 machines the corein order to grind the end of cylindrical crystalline ingot 550 flat. Itis anticipated that the orientation angle of crystalline ingot 550 willbe checked before each pass, of after the number of desired passes.

FIG. 5B shows crystalline ingot 516 which has been secured byrepositionable ingot clamps 538 which are provided on mounting platform526 such that the crystalline ingot 516 will be stable as the end of thecrystalline ingot 516 is being ground flat to the desired angle.

FIG. 6 shows an ingot flat or notch grinding assembly 600 which has beenprovided with 640 table assembly consisting of channels for coolantflow, grinding wheel 630 aligned with the table x-axis 642, which isintended to grind an orientation flat 650 into the aligned surface ofingot 616. X-ray emitter 614 and x-ray collector 612 have also beenprovided so that the orientation of the flat 650 will be accomplishedwith as much precision as possible. It is anticipated that the angularorientation of the ingot 616 will be checked and adjusted as needed on aperiodic and regular basis, for example, with 5 passes of grinding wheel630, or 10 passes, or 12 passes, etc. Ingot 616 has been removablysecured to adjustable tilt platform 618 by means of repositionableclamps 638 provided at opposing ends thereof. Turn crank wheels 628 and615 are provided which allow the operator to manually align adjustabletilt platform 618 with respect to ingot flat or notch grinding assembly600 prior to automatic orientation of the crystal utilizing the x-rayemitter 614, x-ray collector 612. Adjustable tilt platform 618 also hasbeen provided so that ingot 616 may be easily and automaticallyrepositioned if the integral goniometer assembly consisting of x raycollector 612 and x ray emitter 614, determines that the planeorientation of ingot 616 has deviated from proper alignment during theorientation flat or notch grinding process. Adjustable tilt platform 618may be easily and automatically positioned radially about the rotatabley-axis 636, rotatable x-axis 634, and z-axis 632 in order to repositioningot 616 and maintain proper orientation of the crystal plane. Asgrinding wheel 630 descends in the direction of z-axis 632 and bearsupon crystal ingot 616, grinding wheel 630 creates an orientation flat650 in the surface of ingot 616.

FIG. 7 shows wire saw assembly 700 with crystalline ingot 716 attachedto binding piece 720. Crystalline ingot 716 is movable along z-axis 732.Wire saw web 730 is arranged parallel thereto and extends along thelongitudinal axis of crystalline ingot 716 at a length that issubstantially greater than that of crystalline ingot 716.

X-ray emitter 714 and x-ray collector 712 analyze the crystal planes ofcrystalline ingot 716 by rotating crystalline ingot 716 using adjustabletilt platform 718 until a specified crystal plane is found, whereuponthe position of crystalline ingot 716 is locked into place. Crystallineingot 716 is then lowered and slurry 760 containing abrasive material,such as ground diamonds and the like is applied to the cutting areawhere wire saw web 730 meets crystalline ingot 716. Slurry, consistingof abrasive particles (such as silicon carbide or diamond) and oil basedliquid coolant 760 is supplied via supply line 762, and exits dischargejets 764. Adjustable tilt platform 718 allows crystalline ingot 716 tobe repositioned as needed, when intermittent alignment checks performedby goniometer assembly consisting of x-ray emitter 714 and x-raycollector 712 indicate improper alignment of crystalline ingot 716 withrespect to wire saw web 730. This is accomplished by the ability ofadjustable tilt platform 718 to automatically rotate crystalline ingot716 about z-axis 732, rotatable x-axis 735, and rotatable y-axis 737.

FIG. 8 shows wafer and housing assembly 800 with a plurality ofprocessed crystalline wafers 850 within wafer carrier 820 as they may bedelivered to the customer for further processing, or they may be furtherprocessed in house. It is vital at this step that the orientation flat824 be as accurate as possible with respect to the interior crystalconfiguration or alignment of each crystalline wafer 850.

Although in the foregoing detailed description the present invention hasbeen described by reference to various specific embodiments, it is to beunderstood that modifications and alterations in the structure andarrangement of those embodiments other than those specifically set forthherein may be achieved by those skilled in the art and that suchmodifications and alterations are to be considered as within the overallscope of this invention.

What is claimed is: 1.-8. (canceled)
 9. A machining assembly foroptimizing the processing of boules and ingots, the machining assemblycomprising: a machine tool that machines a crystalline substance; a tiltplatform that removably secures the crystalline substance thereto; andan x-ray goniometer that determines alignment of the crystallinesubstance with respect to the machine tool, wherein the tilt platform isautomatically reconfigurable based on the determined alignment toreposition the crystalline substance to maintain proper orientation of acrystal plane therein.
 10. The machining assembly of claim 9, whereinsaid crystalline substance comprises: a boule or an ingot.
 11. Themachining assembly of claim 9, wherein said x-ray goniometer modulecomprises: an x-ray generator and an x-ray collector.
 12. The machiningdevice of claim 11, wherein said x-ray goniometer module furthercomprises: a computerized data processing unit.
 13. The machining deviceof claim 11, wherein said x-ray goniometer module further comprises anindicator device that indicates an interior angle position of saidcrystalline substance to be machined upon said platform.
 14. Themachining device of claim 13, wherein said x-ray goniometer modulefurther comprises a computerized data processing unit and said indicatordevice comprises a display device which indicates the interior angleposition provided by the computerized data processing unit.
 15. Themachining assembly of claim 9, wherein said tilt platform module iscapable of at least one of a directional movement along the x, y and zaxes, or a movement comprising at least one of a yaw, a pitch, and aroll movement.
 16. The machining assembly of claim 15, furthercomprising servomotors capable of moving said tilt platform along the x,y and z axes, and creating yaw, pitch and roll movements.
 17. Themachining assembly of claim 16, further comprising a data processingunit, and said x-ray goniometer is configured to communicate crystalorientation data to said data processing unit, and said data processingunit is configured to communicate the crystal orientation data to saidservomotors of said tilt platform to control orientation or alignment ofsaid crystalline substance during processing.
 18. The machining assemblyof claim 16, wherein said tilt platform is configured to rotate saidcrystalline substance a discrete amount and the x-ray goniometer isconfigured to produce an output signal of intensity of diffracted x-rayscorresponding to each discrete rotation, the machining assembly furthercomprising a data processing unit configured to receive the outputsignal.
 19. The machining assembly of claim 16, wherein said servomotorscommunicate with said tilt platform and said x-ray goniometer so thatcrystal orientation data is determined in real time to adjustpositioning of said tilt platform, thereby permitting precise machiningof said crystalline substance.
 20. The machining assembly of claim 9,wherein said machine tool comprises at least one tool selected from thefollowing group: a machine drill, a machine grinder for rendering asurface flat, a machine grinder for grinding a notch in a crystallinesubstance, a machine polishing element for polishing a crystallinesubstance, and a wire saw.
 21. The machining assembly of claim 9,wherein said x-ray goniometer is configured to determine interioralignment of said crystalline substance with respect to said at leastone machine tool.
 22. The machining assembly of claim 1, wherein saidx-ray goniometer has been positioned substantially adjacent to saidmachine tool and said tilt platform.